1. Field of the Invention
The present invention relates to a resin application apparatus, an optical property correction apparatus and method, and a method for manufacturing a light emitting diode (LED) package, and more particularly, to a resin application apparatus which reduces chromaticity distribution and realizes a target chromaticity, an optical property correction apparatus and method which reproduces a target chromaticity in order to improve a chromaticity distribution, and a method for manufacturing a an LED package which enhances process efficiency.
2. Description of the Related Art
In general, an LED package used as a white light emitting device or the like is implemented by applying transparent resin to protect a light emitting diode (LED) chip mounted on a package body and an electrode connection portion (for example, a bump ball or bonding wire). The transparent resin includes phosphors dispersed therein, depending on the color of light which is to be emitted and implemented by the LED package. The color of light emitted from the LED package has a chromaticity which is decided depending on a mixing ratio of various phosphors and resin (for example, silicon resin) and a content ratio of phosphors when various kinds of phosphors are used. In this case, chromaticity distribution occurs among LED package products having the same target color. Therefore, although if the same light is intended to be emitted, a chromaticity distribution of the light emitted from the LED package products may occur due to process variations which inevitably occur during the LED package manufacturing process, and the chromaticity of light emitted from the varying LED package products may therefore deviate from a target chromaticity range.
FIG. 1 is a flow chart showing a method for manufacturing an LED package according to the related art. Referring to FIG. 1, die bonding is performed to mount and fix an LED chip to a package body or a mounting region of the package body (S11). Then, wire bonding for electrode connection is performed to mount the LED chip on the package body (S13). Subsequently, a dispensing process is performed to dispense transparent resin having phosphors dispersed therein onto the LED chip (S15), and the dispensed resin is cured (S17). Then, the package array is separated into individual LED packages. Finally, the LED packages are tested to determine whether they are a failed product or not (S19). In the testing operation (S19), the optical properties of the individual LED packages are tested.
Although the LED packages are manufactured by the same process, chromaticity, among the optical properties of the LED packages, may have a distribution due to a variety of causes. Accordingly, LED packages deviating from a desired product specification may be produced, which causes a yield reduction and a manufacturing cost increase.
FIG. 2 is a graph showing a chromaticity distribution of the same LED packages and failure occurrence on the Commission Internationale de l'Eclairage (CIE) 1931 chromaticity system. Referring to FIG. 2, the same LED packages with the same model name exhibit a chromaticity distribution, and may deviate from a target chromaticity region. In this case, a failure may occur. Such a chromaticity distribution of the LED packages may be caused by an optical property distribution of LED chips (for example, a distribution of the peak wavelengths or the dominant wavelengths of light emitted from the LED chips) or a property distribution or structural distribution of package elements other than the LED chips.
LED lighting is environmentally friendly as it does not use mercury. Furthermore, it is expected that the LED lighting will contribute to energy conservation. Accordingly, LED lighting is considered to be a main light source which will change the existing lighting market. In accordance with such a trend, many countries such as the United States are promoting the standardization of LED lighting technology so as to spread the acceptance of LED lighting. Therefore, it is important to manufacture an LED package which is capable of satisfying international standards related to LED lighting.
As described with reference to FIG. 1, the testing of the optical property of the LED package in the LED package manufacturing process is performed after the package array is separated into individual LED packages. This may reduce the efficiency of the optical property test operation. As a result, the productivity of the LED package manufacturing process may decrease.
FIG. 3 is a plan view of an LED package immediately before a package array is cut into separate LED packages in the LED package manufacturing process, that is, before a package singulation operation. Referring to FIG. 3, an LED chip 3 is attached to a package body 2 installed in a lead frame 1, and electrodes 5 of the lead frame 1 (or electrodes of the package body 2) are bonded by a wire 4. Transparent resin containing phosphors is applied onto the package body 2 so as to cover the LED chip 3 and the wire 4. A plurality of LED packages 6 are connected in an array by the lead frame 1. FIG. 3 illustrates one LED package region in such an array. In a subsequent process, the lead frame 1 is cut so that each package region may obtain a singulated LED package 6. A voltage is applied to the singulated LED package 6 such that the LED package 6 may emit light, and an optical sensor or the like is used to measure the chromaticity of the LED package 6. Depending on the application amount of the phosphor-containing resin, the chromaticity of the light (for example, white light) emitted from the LED package 6 may differ. The chromaticity of the LED package 6 is one of the most important specifications of the LED package 6. When the chromaticity of the LED package 6 deviates from a predetermined range, the LED package 6 becomes a failed product.
Referring to FIG. 3, both electrodes of the LED package 6 are electrically connected by the lead frame 1. Therefore, before the LED package 6 is separated from the lead frame 1, the LED package 6 cannot emit light. As a result, before the LED package 6 is separated from the lead frame 1, the chromaticity of the LED package 6 cannot be measured. Accordingly, when the optical properties of the LED packages 6 are to be tested, the LED packages 6 should be separated from the lead frame 1, and a voltage should be applied to each of the LED packages 6 to test the optical properties thereof. As such, since the optical property test for the plurality of LED packages 6 cannot be performed on the lead frame 1 and should be performed for each of the singulated LED packages 6, the operation efficiency inevitably decreases, thereby causing a reduction in productivity. Furthermore, as a result of the optical property test, it may be determined that the amount of phosphors contained in the phosphor-containing resin is insufficient. In this case, there are difficulties in automating and performing a process for supplementing the phosphors contained within the LED package 6.